Public Constructors

Throws

Public Methods

public
int
available()

Returns an estimated number of bytes that can be read or skipped without blocking for more
input.

Note that this method provides such a weak guarantee that it is not very useful in
practice.

Firstly, the guarantee is "without blocking for more input" rather than "without
blocking": a read may still block waiting for I/O to complete — the guarantee is
merely that it won't have to wait indefinitely for data to be written. The result of this
method should not be used as a license to do I/O on a thread that shouldn't be blocked.

Secondly, the result is a
conservative estimate and may be significantly smaller than the actual number of bytes
available. In particular, an implementation that always returns 0 would be correct.
In general, callers should only use this method if they'd be satisfied with
treating the result as a boolean yes or no answer to the question "is there definitely
data ready?".

Thirdly, the fact that a given number of bytes is "available" does not guarantee that a
read or skip will actually read or skip that many bytes: they may read or skip fewer.

It is particularly important to realize that you must not use this method to
size a container and assume that you can read the entirety of the stream without needing
to resize the container. Such callers should probably write everything they read to a
ByteArrayOutputStream and convert that to a byte array. Alternatively, if you're
reading from a file, length() returns the current length of the file (though
assuming the file's length can't change may be incorrect, reading a file is inherently
racy).

The default implementation of this method in InputStream always returns 0.
Subclasses should override this method if they are able to indicate the number of bytes
available.

Returns

the estimated number of bytes available

Throws

public
void
mark(int readlimit)

Sets a mark position in this InputStream. The parameter readlimit
indicates how many bytes can be read before the mark is invalidated.
Sending reset() will reposition the stream back to the marked
position provided readLimit has not been surpassed.

This default implementation does nothing and concrete subclasses must
provide their own implementation.

Parameters

readlimit

the number of bytes that can be read from this stream before
the mark is invalidated.

Returns

public
int
read(byte[] buffer)

Throws

public
int
read()

Reads a single byte from this stream and returns it as an integer in the
range from 0 to 255. Returns -1 if the end of the stream has been
reached. Blocks until one byte has been read, the end of the source
stream is detected or an exception is thrown.

Throws

public
long
skip(long count)

Skips at most byteCount bytes in this stream. The number of actual
bytes skipped may be anywhere between 0 and byteCount. If
byteCount is negative, this method does nothing and returns 0, but
some subclasses may throw.

Note the "at most" in the description of this method: this method may
choose to skip fewer bytes than requested. Callers should always
check the return value.

This default implementation reads bytes into a temporary buffer. Concrete
subclasses should provide their own implementation.